Abstract
The quest for lightweight materials with exceptional energy absorption capabilities has intensified in recent years, driven by the need to engineer robust structures for critical applications such as aerospace, transportation, and nuclear reactor containment. This paper presents a comprehensive study on the design and evaluation of bio-inspired composite quasi-scale specimens under quasi-static loading, with the aim of maximizing energy absorption efficiency. Drawing inspiration from the unique dermal armor of the pangolin, a distinctive mammalian species, we explore the use of sustainable plant fibers, including luffa and linen, as alternatives to traditional glass fibers. The Taguchi method, a robust statistical approach, is employed to systematically investigate the influence of various parameters on the Total Absorbed Energy (TAE) and Specific Absorbed Energy (SAE). A total of five parameters—fiber type, radius of curvature, number of composite plies, and the dimensions of the trapezoidal scales (Y1 and Y2)—are assessed for their impact on energy absorption. The experimental setup involves fabricating composite specimens using unsaturated isophthalic polyester resin as the matrix, and subjecting them to quasi-static lateral compressive loading. The energy absorption characteristics are analyzed by examining the force-displacement data, with the TAE inferred from the area beneath the curve and the SAE calculated by dividing TAE by the specimen's mass. The results indicate that luffa fibers exhibit superior TAE compared to linen and glass fibers, while linen fibers demonstrate higher SAE. The Taguchi method facilitates the identification of optimal parameter levels for maximizing energy absorption, with the predicted optimal specimen exhibiting a TAE of 11.2431 J and an SAE of 2.3677 J/g, closely matching experimental verification with errors of 5.76% and 3.94%, respectively. Theoretical analysis, incorporating the Rigid Perfectly Plastic (RPP) and Hollomon material models, elucidates the mechanisms underlying energy dissipation, including curvature flattening and plastic hinge formation. This framework provides a robust basis for predicting the energy absorption behavior of bio-inspired composite structures, offering insights into the design of advanced materials with enhanced performance characteristics. The study underscores the potential of bio-inspired designs in addressing contemporary engineering challenges, highlighting the synergy between natural forms and advanced materials science in the pursuit of sustainable and high-performance structural solutions.